Manufacture of peroxidic compounds



United States Patent 3,187,055 MANUFACTUM 0F PEROXIDIC CORWUUNDS GodfreyPaul Armstrong, Kingswood, Reginald Harold Hall, Sutton, Denis CheseidenQuin, Teddington, and Kari Heinrich Walter Turck, Banstead, England,assignors, by mesne assignments, to Hercules Powder Company, acorporation of Delaware No Drawing. flriginal application Mar. 19, 1948,Ser. No. 15,954, now Patent No. 2,632,772, dated Mar. 24, 1953. Dividedand and this application Nov. 13, 1952, Ser. No. 32%,336 Ciaimspriority, application Great Britain, Dec. 9, 194-7, 32,397/47 7 Ciaims.{CL 260-610) This application constitutes a division of our applicationfor United States Letters Patent, Serial No. 15,954, filed March 19,1948, now US. Patent No. 2,632,772, issued March 24, 1953.

The present invention relates to improvements in and a process for theproduction of peroxides from isopropyl benzene. By the expressionperoxides" is meant the peroxide as well as the hydroperoxide.

The preparation of isopropyl benzene peroxide from isopropyl benzene hasbeen described by Hock and Lang in Berichte (1944), vol. 77, page 257.They proceeded by shaking the said hydrocarbon with dry oxygen withconcurrent exposure to shortwave irradiation. In this way they succeededin converting into the corresponding hydroperoxide not more than 24grams out of 360 grams of isopropyl benzene treated within 24 hours,that is, 2.4 grams per hour per litre or an overall rate ofapproximately 0.3% by weight per hour. It is evident that such a processcannot form the basis for large scale production. A technically feasibleprocess on the other hand becomes of primary importance since the saidperoxidic compounds may form intermediates for the economicalpreparation of phenolic compounds.

It has been found, furthermore, that when liquid hydrocarbons of thekind indicated above are subjected toan oxidation treatment by bringingthem into intimate contact with molecular oxygen the oxidation proceedsextremely slowly for a considerable time at the start, and during thisinduction period the rate of oxygen absorption increases only gradually.The addition of certain catalysts such as copper may overcome thisdifficulty but generally leads to a considerably lower efliciency asregards the production of peroxidic compounds and frequently results inthe production of large amounts of carbon dioxide by complete combustionof the starting material.

It is an object of this invention to provide a process which makes thecommercial production of peroxidic compounds from isopropyl benzenepossible. It is another object of the invention to reduce the inductionperiod for the oxidation reaction to a minimum and thus increase theoverall yield of the peroxidic compounds over a certain time.

According to the present invention isopropyl benzene peroxide isproduced by bringing isopropyl benzene in the liquid phase, in theabsence of heavy metal oxidation catalysts, into intimate contact withmolecular ox gen at temperatures between 78 and 150 C. and adding to thereaction mixture fresh isopropyl benzene continuously or intermittentlywhilst the oxidation reaction proceeds.

Preferably the addition of the fresh isopropyl benzene to the reactionmixture is started after the rate of oxidation in the said mixture hasbecome practically constant. A preferred method of carrying out theprocess in practice consists in withdrawing an amount of the reactionmixture corresponding to and commensurate with the Patented June 1, 1%65quantity of fresh isopropyl benzene added thereto, so that the volume ofthe reaction mixture in the reactor remains constant.

By introducing fresh isopropyl benzene to the reaction mixture inoperation the rate of oxidation per unit volume is not decreased as wasto be expected judging from the fact that with the fresh isopropylbenzene fresh material which had been inhibiting or retarding theoxidation at the start is continuously added to the reaction mixture. Itis therefore surprising that in spite of the continuous addition of thefresh isopropyl benzene according to the invention a high rate ofoxidation of the starting material per unit volume is maintained.

The molecular oxygen for the oxidation may be in the form of practicallypure oxygen, of gases rich in oxygen such as commercial oxygen or in theform of gas mixtures which are richer in oxygen than is air. The use ofsuperatmospheric pressure is advantageous.

The presence of ozone in the gases containing oxygen has also proved tobe advantageous. The'use of short wave irradiation is not necessary forcarrying out the process of the invention, but may be advantageous insome cases.

Furthermore, Hock and Lang (loc. cit.) have stated that in the case ofisopropyl benzene decomposition of the peroxide formed does not beginbelow a temperature of from l170 C. We have found, however, that acertain decomposition of the percompounds occurs during the oxidationwhich all ects adversely the yields of percompounds produced, even whenthe temperatures during the oxidation operation are kept below saidtemperatures. This decomposition depends apparently on the concentrationof the peroxidic compounds present in the reaction mixture. It is,therefore, a further object of this invention to reduce thisdecomposition and keep it at a minimum. This is achieved by feedingfresh isopropyl benzene to the reaction mixture and withdrawing thecommensurate amount of the latter at such a rate that the amount fed inis more than twice, preferably more than three to four times, the amountwhich under the prevailing conditions is oxidized during the same time,so that the peroxide concentration in the reaction mixture does notexceed 50% and is preferably less than 25%. The residence time of thereaction mixture in the reactor is therefore comparatively short wherebythe decomposition of the peroxide already formed in the mixture isminimized.

It is advantageous to provide for the presence .111 the reaction mixtureof small amounts of alkali. These amounts are preferably at leastsufiicient to neutralize any carboxylic acids which are present or maybe formed during the reaction. A small excess of alkali in the reactionmixture will not disadvantageously influence the oxidation reaction.

As alkali may be used the carbonates or hydroxides of alkali metals,such as sodium and potassium hydroxide, also the oxides or hydroxides ofalkaline earths such as calcium and barium, the normal phosphates of thesaid metals, ammonia and the like. It has been found convenient to addfor instance the hydroxides in the form of a concentrated aqueoussolution, whereby a kali metal carbonates, e.g., sodium or potassiumcarabonate, they occur in solid form in isopropyl benzene at'theaforesaid reaction temperatures of 70 to 150? C. when isopropyl benzeneis used alone as aforesaid.

On the other hand, a liquid diluent which is 'imiscible with isopropylbenzene may be used in conjunction with the isopropyl benzene. In thiscase the liquid phase is heterogeneous. As such'diluent any liquidimmiscible with isopropyl benzene and not harmful to or harmfully Iaffected by the oxidationreaction may be employed.

Such a diluent is for instance water. When'a diluent such as waterisused in which the alkali is soluble, then, to the extent that thealkali is dissolved therein, it is present in the reaction mixture inthe form of a solution in the diluent.

. The preferred method for carrying out the oxidation in the presence ofWater is to introduce the oxygen into an oil-in-water dispersionprepared advantageously with the aid of emulsifying agents such assodium ricinoleate or lauryl sulfate as described in the copendingpatent application Serial No. 738,726, now US. Patent No. 2,547,938,issued April 10,1951. In this case the isopropyl benzeneand the aqueousphase are continuously 'or intermittently' fed into the reactor,provision being tion by volume of five of Water to one of isopropylbenzene gave useful results and allowed the production of aconcentration of 30% and more of peroxides in the reaction mixture withan efliciency of 80%and more.

The temperature advantageously maintained inthe dispers'ed reactionmixture is within the range of 80 to 120 C. preferably about 100 C. Inthis case the addition to the oil-in-water dispersion of alkalinesubstances is effected with advantage by adding alkali hydroxides insuch amounts that a pH between 7.5' and 10.5 is maintained' in theaqueous phase. Asthe pH value changes during the progress of theoxidation it is advantageous to maintain the pH value at the said levelby periodical addition of small quantities of said alkali;

- When water is used as diluent in the manner described 7 v the freshisopropyl benzene is added to the reaction mixture according to thisinvention preferably in the form of an oil-in-water dispersion. Theliquid mixture with drawn from the reactor comrnensurately with the saidaddition is preferably transferred to a decanter wherein the aqueousphase separates from the oil phase which latter contains the greaterpart of the peroxide formed dissolved in unchanged isopropyl benzene.The aqueous phasemay then be returned with great advantage to thereactor oxidizer. On reusing the aqueous phase for the oil-in-waterdispersion the oxidation sets in immediately even if the process iscarried out as a batch process and theabsorption of the oxygen by theisopropyl benzene reaches its maximum rate almost at once.

When using the alternative method for carrying the invention into effectcomprising introducing the oxygen or oxygen containing gases intoisopropyl benzenein the homogeneous liquid phase,the most favorabletemperatures, within the above-mentioned range of 70 to 150 C. arebetween 115 and 150 C. and especially 120 efficiency as hereinafterdefined drops to" 80% and less.

lowed by therein. 7

, 4. It is therefore a special feature of the invention when oxidizingthe isopropyl benzene in the homogeneous liquid phase to limit the timeof reaction and of residence in the reaction zone so that the efficiencyof the process does not fall below Byefliciencyis meant here theproportion of moles ofperoxide in the reaction mixture to the number ofmoles of oxygen absorbed by moles of isopropyl benzene The proportion ofperoxide in the reaction mixture, i.e., its concentration per 100 molesV 'of isopropyl benzene initially present is determined by initiallypresent.

the withdrawal of samples of they reaction mixture fol iodometrictitration of the peroxide content It is therefore possible toobtain ahighrate of hourly output of peroxide provided that the time. ofoxidation is restricted.

The following Tables IA and 1B refer to batch experiments and show that"the efficiency has initially a high value, and that this decreases asthe oxidation reaction proceeds; the rate of decrease of the efficiencyis at first slow but later becomes considerably more rapid beyond thepoint where the peroxide concentration is at a maximum and theefiiciency about 80% TABLE IA [At C.]'

Time, hours 7 Rate Peroxide Efticiency concentration TABLE 'IB Time,hours Rate 7 Peroxide Etficiency concentration 7 time of the reactionmixture inthe reaction zone should be as short as possible. It istherefore preferrer to remove the reaction mixture from the 'reaction'zone as soon as or before the oxidation reaction reaches those limitsand preferably to cool it so that further decomposition is prevented. As'on the other hand the oxida 7 tion proceeds at .a very much higher ratewhen the temperature is near the upper limit,tit is afurther feature ofthis invention to carry out the oxidation at the start at the highertempertaure, i.e., at about to C. and then to reduce the temperature inthe reaction mixture to 125 C. r

and proced with the oxidation at about 11 5" The figure given in theTables IA and IB were obtained by tests carried out in a batchwisemanner.

The second columns of the above Tables IA and IB, show that the rate ofoxygen absorption rises in each run until it reaches a maximum. At 120C. this maximum rate of absorption is attained after about 7 hours, andat 130 C. after about four hours. Thereafter it falls fairly rapidlyuntil the rate of oxygen absorption has dropped to approximately onethird to one quarter of the maximum rate during the last hour indicatedin the tables. The eihciency, as can be seen, remains high, that isabout 90% and more, whilst the oxygen absorption rate rises and theperoxide concentration increases. It is therefore a preferable featureof this invention to stop the introduction of oxygen into the reactionmixture Whilst the rate of oxygen absorption is still increasing. Inthis manner the best use is made of the oxygen introduced into thereaction mixture and of the isopropyl benzene, before the decompositionof the peroxide formed leads to any substantial extent to the formationof undesired by-products.

The method, by which the residence time required to maintain any desiredconditions in a continuous process may be calculated approximately fromresults obtained in a batch process carried out under similartemperature conditions, is illustrated in Table 11 below. The desiredcondition to be maintained in a continuous process is here, forinstance, a peroxide concentration of 8%, and the figures given for therate and efficiency are those obtained in a batch process at thetemperature indicated when the peroxide concentration reaches thisfigure. The residence time is then calculated using the expression:

Residence time:

Peroxide concentration X 100 Rate Xefficiency The terms PeroxideConcentration and Rate have here the same meaning as hereinbeforedefined. The term Efliciency here used is the proportion of moles ofperoxide produced to moles of oxygen absorbed by 100 moles of isopropylbenzene over a short period (e.g., 1 hour) which is chosen to correspondto the time at which the other quantities are recorded.

When the process of the invention is carried out in the homogeneousliquid phase, i.e., a liquid phase in which no immiscible diluent ispresent, the alkaline substances which are to neutralize the carboxylicacids present or formed during the reaction may be added in the form ofa concentrated aqueous solution of water-soluble alkaline compounds suchas alkali metal hydroxides.

The quantity of alkali added is with advantage adjusted in such a waythat when a filtered sample of the reaction mixture is extracted withabout twice its volume of distilled water the pH value of the aqueousextract is not less than 4- when measured electrometrically. In thecontinuous process the alkaline substance is advantageously introducedinto the system with the fresh isopropyl benzene. Apart from preventingthe corrosion of iron vessels and the formation of soluble metalcompounds the effect of the alkali addition is that the maximum rate ofoxygen absorption is higher and is reached in a shorter time, and thatthe peroxide concentration in the reaction mixture is greater than inthose obtained in the absence of alkali. In other respects such as theefiiciency the course of the reaction in the presence of alkali is verysimilar to that which the process takes in the absence of the alkali.The alkaline substances are preferably added in the form of concentratedsolutions, for instance, of alkali metal hydroxides in order tofacilitate their introduction and their uniform distribution. The amountof water in the solution is advantageously limited so that at thereaction temperature it is evaporated with great rapidity and so thatthe alkaline substances thereby become distributed in the isopropylbenzene in the form they assume when the water contained in the addedsolution has been evaporated, this being solid crystalline form in thecase of an alkaline substance such as sodium carbonate. At any rate, theamount of water should be so limited that substantially no heterogeneousliquid phase is formed in the reaction mixture.

The oxidation process in the homogeneous liquid phase may be carried outconveniently in a tower or similar apparatus, into one end of which theisopropyl benzene, preferably preheated or partly preoxidized is fed,Whilst at the other end the isopropyl benzene peroxide containing thereaction product is withdrawn continuously or periodically in such a waythat the concentration of peroxide within the tower or apparatusincreases in the direction of the flow of the liquid. The dimensions ofthe tower and the volume of isopropyl benzene passed through said towerin the time unit are adjusted so that the residence time in the saidtower fulfills the features of this invention, namely, that the liquidreaction mixture leaves the tower before the efiiciency drops below orbefore the maximum rate of oxygen absorption thereby is attained.

It is also possible to carry out the process in a series of continuousreaction vessels, each of which works on a certain peroxide level. Thefresh isopropyl benzene fed into the tower or the first of the series ofreaction vessels contains preferably some previously formed peroxide toinitiate the oxidation reaction.

For carrying out the process of the present invention it is preferred touse isopropyl benzene for the oxidation which is free from unsaturatedcompounds such as styrenes and/or substances which act as catalysts fordecomposition of the peroxide formed during the oxidation.

' Styrene and styrene compounds such as methyl styrene produce adeleterious eiiect upon the oxidation reaction even in such minutequantities as 50 parts per million (ppm). Said compounds may be removed,for instance, by washing with sulfuric acid and/or alkali metalpermanganate solution or by their conversion into separate compounds byhydrogenation, for instance, by means of Raney nickel. It is howeverpossible to use in the process according to this invention commercialisopropyl benzene which has been purified by a single distillation onlyand to maintain the oxidation at a high rate as soon as it is onceestablished. It is however preferred to use isopropyl benzene which hasbeen previously purified by the means described above as the efficiencyof the oxidation reaction is better with purified isopropyl benzene thanwhen isopropyl benzene is used which has not been purified. Substanceswhich act as catalysts for the decomposition of the peroxide are, forinstance, soluble compounds such as copper, cobalt, manganese and thelike. It is, however, possible to carry out the oxidation in metalreactors which are not attacked under the conditions of the reaction,such as, for example, mild steel in the presence of alkali.

The isopropyl benzene peroxide formed may be isolated from the reactionmixture in the Well-known manner or may be subjected immediately todecomposition for the manufacture of acetone and phenol.

The following examples show the manner in which the process of theinvention may be carried out in practice.

Example 1 In a stirring vessel, fitted with an overflow seal and.

1.4 grams of sodium stcarate and 5.3 grams of sodium.

carbonate (Na CO was vigorously stirred while oxygen (about 90% waspassed through the mixture. The temperature was kept at 85 C. After 10/2 hours, the reaction mixture contained 48.2 grams of peroxide(calculated as isopropyl benzene peroxide), which corresponds to anaverage hourly production of 4.6 grams of peroxide. 7

From this time onward 59 cc. of isopropyl benzene containing 0.65%weight by volume (w./v.) stearic acid and 118 cc. water containing0.048% w./v. sodium hydroxide and 0.75% w./v. sodium carbonate werecontinuously fed to the oxidizer per hour, while at the same Example 2The oxidizer was charged with 200 cc. of isopropyl benzene free fromperoxides and styrenes, and 400 cc. of

water containing 1.4 grams of sodium stearate and 5.3 grams sodiumcarbonate. As soon as the agitation was started an emulsion formed.Oxygen was admitted and the temperature kept at 85 C. After a period of1% hours the rate of absorption increases steadily. After 9.3 hours therate of absorption was 1.2 litres per hour (4.0 mole percent/hr.) atotal of 5.4 litres having been absorbed. The peroxide concentration was14 mole percent on the isopropyl benzene.

Fresh isopropyl benzene and water containing sodiumstearate and sodiumcarbonate in the same proportions.

as indicated above were then introduced at the rate of 45 cc. ofisopropyl benzene and 90 cc. of aqueous phase per hour. The absorptionrate of oxygen continued to increase with no return to the inductionperiod.

After a total reaction time of 29.3 hours the peroxide concentration hadincreased to 29 mole percent on the isopropyl benzene. Since a total of1100 cc. of isopropyl benzene had been introduced from the start, thetotal amount of peroxide produced was 2.3 moles or 348 grams ofisopropyl benzene peroxide. A total of 66.7 litres of oxygen had been.absorbed from the start of the experiment.

' Example 3 Into a reactor fitted with an overflow and having a liquidcapacity of 185 cc. were fed 370 cc. of purified isopropyl benzene perhour to which was added 0.05 cc. of a 50% NaOH solution every 10 hours.Through the overflow this vessel communicated with another vessel withan overflow volume of 700 cc. To the contents of this vessel was added0.05 cc. of a 50% NaOH solution every 6 hours.

In the first reactor the temperature was maintained at 140 C. whilstoxygen of about 90% purity was introduced and absorbed at the rate of9.2 mole percent per hour. and the concentration of the peroxideproduced in this vessel was 4.4 mole percent. The temperature in thesecond vessel was kept at 130 C. The oxygen absorption in this vesselamounted to 11.4 mole percent per hour and the produced peroxideamounted to 23. mole percent concentration. The residence time in thisvessel was '1 hour 3 minutes.

The eiiiciency in the first vessel was 96% whilst the The residence timein this vessel was 30 minutes & efi'iciency in the second was 86%; thetotaloxygen ab sorbed by the contents of the two vessels per 100 molesof isopropyl benzene initially fed into the first vessel came to.26.1moles and the total ofperoxide formed to 22.9 moles, the efiiciencyover both stages thus being 88%.

Example 4 i A reaction vessel equipped with a high speed agitator wascharged with 150 cc. of purified isopropyl benzene to' which 0.1 cc. ofa'20% aqueous solution of sodium hydroxide had been added. The contentsof the vessel were heated to 130 C. and oxygen of about 98% purity wasintroduced into the reactor. Absorption started Within 15 minutes andthe rate of absorption was 5.8 mole percent in the first hour of which100% was converted into peroxide. In the second hour the oxygenabsorption was 17.4 mole percent and the eificiency was 97%. Theabsorption of oxygen by the reaction mixture in the third hour was 20.6mole percent, whilst the efficiency dropped to 93%. The oxygen'introduction was then stopped before the absorption rate reached itspreviously ascertained maximum.

Example 5 isopropyl benzene was oxidized in a mild steel vessel of 2gallons'capacity, equipped, with a stirrer, liquid overflow, refluxcondenser and oxygen inlet line. The vessel was charged with isopropylbenzene purified by a single hydrogenation of a commercial product, andcontaining less than 40 p.p.m. of styrenes, and with 7 cc. of a 50%solution of sodium hydroxide. The temperature of the charge was raisedto 130 C. and oxygen of 95% purity introduced. Absorption of oxygenstarted after a short time and after 0.5 hour had'reached 9 mole percentper hour; at this point continuous feeds of fresh isopropyl benzene(similar to that used for the initial charge) and of 50% sodiumhydroxide solution were started, and a corresponding volume of theoxidation product removed from the vessel continuously by way of theoverflow.

At a later stage of the run a feed of untreated commercialisopropyl'benze-ne containing about 500 p.p.m. of ix-met'hylstyrene wassubstituted for the hydrogenated material, and the conditions wereadjusted so that the peroxide concentration in the product remainedsubstantially constant. .The figures for the steady conditions obtainedare also given below.

I Hydrogenated Untreated Feed material commercial commercial isopropylisopropyl benzene benzene Isopropyl benzene feed rate (litres per hourper litre volume of reaction qul 0.62 0. 54 Alkali feed rate (cc. 50%NaOH per litre volume of reactionliquid) 0. 5 0. 5 Oxygen absorptionrate (moles per 1 21 7 I hour per moles of isopropyl ben- 9 Zena) 13. 514. 2 Peroxide make, crams/hn/l 134 122 Peroxide concentration inproduct (percent by weight) 23. 9 24. 7 Etficiency of peroxideproduction (1% on O; consumed) a- 91 88 1 Litres perv hour per litre.Example 6 A mild steel pot of about 9 litres capacity was charged with2.3 litres of isopropyl benzene and 5.7 litres of Water. The mixing ofthe oil and the aqueous phase was accomplished by means of a recyclestirrer. Attached to the separator was a small decanter of about 50 cc.capacity wherein the oil and aqueous phase separated, the oiloverflowing and the aqueous phase being returned from the bottom ofthereactor, Oxygen and fresh isopropyl benzene were fed ih through thelid of the reactor. The

a temperature in the reaction mixture was maintained between 84 and 86C.

Fresh isopropyl benzene was added at a rate of 0.3 litres/hour whereby asimilar amount of reaction mixture overfiowed from the decanter. Oxygenwas introduced into the system and absorbed by the reaction mixture at arate of 13.09 litres/hour. In the oil which had overflowed from thedecanter the peroxide concentration amounted to 25.6 grams in each 106cc. and the total peroxide production during 24 hours thus came to 184grams with an efiiciency regarding oxygen consumption of 86% and aconversion of isopropyl benzene to isopropyl benzene peroxide calculatedon the oxygen used of 21%.

What we claim and desire to protect Letters Patent is:

1. In a process for oxidizing cumene to cumene hydroperoxide in liquidphase with elemental oxygen as oxidizing agent, the improvement whichcomprises providing and maintaining solid alkali metal carbonate incontact with said cumene and employing temperatures in the range fromabout C. to about 150 C.

2. in a process for oxidizing cumene to cumene hydroperoxide in liquidphase with elemental oiq gen as oxidizing agent, the improvement whichcomprises providing and maintaining solid sodium carbonate in contactwith said curnene and employing temperatures in the range from about 70C. to about 150 C.

3. In a process for oxidizing cumene to cumene hydroperoxide in liquidphase with elemental oxygen as oxidizing agent, the improvement whichcomprises providing and maintaining solid sodium carbonate in contactWith said cumene and. employing temperatures in the range from above 90C. to about 130 C.

4. In a process for oxidizing cumene to curnene hydroperoxide in liquidphase with elemental oxygen as oxidizing agent, the improvmcnt whichcomprises providing and maintaining solid sodium carbonate in contactwith said cumene and employing temperatures in the range from about C.to about C.

5. In a process for oxidizing cumene to curnene hydro- 1Q peroxide inliquid phase with elemental oxygen as oxidizing agent, the improvementwhich comprises providing and maintaining solid sodium carbonate incontact with said cumene and employing a temperature of about 130 C.

6. In a process for oxidizing cumene to cumene hydroperoxide in liquidphase with elemental oxygen as oxidizing agent, the improvement whichcomprises effecting said oxidation in homogeneous liquid phase in thepresence of alkali metal carbonate provided in the reaction mixture andemploying temperatures in the range from about 115 C. to about C.

'7. In a process for oxidizing cumene to cumene hydroperoxide in liquidphase With elemental oxygen as oxidizing agent, the improvement whichcomprises effecting said oxidation in homogeneous liquid phase in thepresence of alkali metal carbonate provided in the reaction mixture andemploying temperatures in the range from about 70 C. to about 159 C.

References Cited by the Examiner UNITED STATES PATENTS 2,430,864 11/47Farkas et al. 2,447,400 8/48 Emerson et al 260-618 X 2,447,794 8/48Brewer. 2,484,841 10/49 Lorand. 2,632,772 3/53 Armstrong et al.2,632,773 3/53 Armstrong et al. 2,632,774 3/53 Conner et a1. 260--6102,681,936 6/54 Jon's.

FOREIGN PATENTS 481,560 4/48 Belgium. 4? 6,995 7/ 51} Belgium.

LEON ZITVER, Primary Examiner.

EARL W. HUTCHISON, NATHAN MARMELSTEIN,

CHARLES B. PARKER, Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No3,187,055 June 1, 1965 Godfrey Paul Armstrong et a1,

It is hereby certified that err en't requiring correction and that thcorrected below.

( SEA L) Auest:

ERNEST W. SWIDEH EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

1. IN A PROCESS FOR OXIDIZING CUMENE TO CUMEME HYDROPEROXIDE IN LIQUIDPHASE WITH ELEMENTAL OXYGEN AS OXIDIZING AGENT, THE IMPROVEMENT WHICHCOMPRISES PROVIDING AND MAINTAINING SOLID ALKALI METAL CARBONATE INCONTACT WITH SAID CUMENE AND EMPLOYING TEMPERATURES IN THE RANGE FROMABOUT 70*C. TO ABOUT 150*C.